1. Field of Invention
The present disclosure relates in general to a method of detecting subterranean bed boundaries using interferometric processing. More specifically, the present disclosure relates to interferometric processing of low frequency resistivity log data to locate a subterranean bed boundary during earth boring procedures.
2. Description of Prior Art
A resistivity measurement is one typical subterranean formation evaluation procedure where a log of the resistivity adjacent a wellbore is measured. Formation resistivity is a function of any fluids trapped within the subterranean formation. Thus resistivity is often measured to identify where water and/or hydrocarbon are present in the formation. Changes in resistivity in a subterranean formation can be abrupt and define a bed boundary. Resistivity can be measured with a wireline tool or a logging while drilling (LWD) tool. Measuring resistivity with a galvanic (DC) resistivity device typically involves forming an electrical potential in the formation and measuring a voltage between voltage measuring electrodes of the device. In an induction measurement device, magnetic flux/magnetic field is induced in the formation by the current in the transmitter; which induces a measured voltage in a receiver of the tool spaced axially from the transmitter. However, during LWD operations, there is a desire to “look ahead” so as to avoid drilling across bed boundaries or faults, as well as any subterranean geological hazard.